Tissue adhesives have many potential medical applications, including topical wound closure, supplementing or replacing sutures or staples in internal surgical procedures, adhesion of synthetic onlays or inlays to the cornea, drug delivery devices, and as anti-adhesion barriers to prevent post-surgical adhesions. Conventional tissue adhesives are generally not suitable for a wide range of adhesive applications. For example, cyanoacrylate-based adhesives have been used for topical wound closure, but the release of toxic degradation products limits their use for internal applications. Fibrin-based adhesives are slow curing, have poor mechanical strength, and pose a risk of viral infection. Additionally, the fibrin-based adhesives do not covalently bind to the underlying tissue.
Several types of hydrogel tissue adhesives have been developed, which have improved adhesive and cohesive properties and are nontoxic. These hydrogels are generally formed by reacting a component having nucleophilic groups with a component having electrophilic groups, which are capable of reacting with the nucleophilic groups of the first component, to form a crosslinked network via covalent bonding. However, these hydrogels typically swell or dissolve away too quickly, or lack sufficient adhesion or mechanical strength, thereby decreasing their effectiveness as surgical adhesives.
Examples of hydrogel tissue adhesives are described by Sehl et al. in U.S. Patent Application Publication No. 2003/0119985. The adhesives are formed by reacting a hydrophilic polymer, such as collagen, with a crosslinkable component having nucleophilic groups and a crosslinkable component having electrophilic groups. The crosslinkable components include various activated forms of polyethylene glycol. Goldmann et al. in WO 03/035122 describe a hydrogel tissue adhesive formed by reacting chitosan or a modified polyvinyl alcohol bearing amino groups with an oxidized polysaccharide, such as oxidized dextran. Neither of these disclosures describes a polymer adhesive formed by reacting an oxidized polysaccharide with a water soluble, multi-arm polyether amine.
Therefore, the problem to be solved is to provide a tissue adhesive material with improved characteristics for use in surgical procedures as well as other medical applications. Applicants have addressed the stated problem by discovering a polymer tissue adhesive formed by reacting an oxidized polysaccharide with a water-soluble, multi-arm polyether amine as disclosed in U.S. patent application Ser. No. 11/244,756, filed on Oct. 6, 2005 and published as US 2006/0078536 A1.
Applicants herein further address the stated problem by discovering a tissue adhesive having modified elasticity and improved stability derived from reacting an oxidized polysaccharide with a chain-extended polyamine product of the invention.